The teres major (Latin: musculus teres major) is a flat muscle of the shoulder girdle.
The teres major originates from the posterior aspect of the inferior angle of the scapula and from the lower part of the lateral border of the scapula.
Fibers of the teres major attach to the crest of the lesser tubercle of the humerus.
The main functions of the teres major muscle are adduction, extension and internal rotation of the upper arm.
The teres major is innervated by the subscapular nerve.